Edge seal for absorbent article and method for making

ABSTRACT

A disposable diaper comprising a topsheet, a backsheet, and an absorbent core disposed between the topsheet and backsheet. The topsheet and backsheet define a periphery and longitudinal edges, portions of the longitudinal edges define leg openings when the diaper is worn. The diaper has a discrete edge seal folded about and joined to the longitudinal edges at least at the portions defining leg openings when the diaper is worn. An apparatus for affixing a discrete edge seal onto a portion of a longitudinal edge of a continuous web and methods for affixing a affixing discrete edge seal onto a predetermined portion of a longitudinal edge of a continuous web are also provided.

CROSS REFERENCE

[0001] This application claims priority to European Patent ApplicationNo. 01122697.1 filed on Oct. 1, 2001.

FIELD OF THE INVENTION

[0002] This invention relates to edge seals on absorbent articles, andmore particularly to discrete edge seals, such as, discrete/ elasticizededge seals on disposable absorbent articles, such as diapers.

BACKGROUND OF THE INVENTION

[0003] Infants and other incontinent individuals wear disposableabsorbent articles such as diapers to receive and contain urine andother body exudates. Absorbent articles function both to contain thedischarged materials and to isolate these materials from the body of thewearer and from the wearer's garments and bed clothing. Disposableabsorbent articles having many different basic designs are known to theart.

[0004] A typical absorbent article has a chassis that includes a liquidpervious topsheet, and a liquid impervious backsheet joined to thetopsheet. An absorbent core is typically positioned between the topsheetand the backsheet. The chassis has a generally elongated shape, whichcan be rectangular or hourglass shaped. The long dimension of thechassis defines two opposed edges referred to as the longitudinal edges.A portion of each longitudinal edge defines the leg opening of thediaper when worn.

[0005] To better contain body exudates, absorbent articles often haveelasticized leg openings, referred to as leg cuffs that are designed tofit snugly about the legs of the wearer. Leg cuffs can be made by simplyplacing tensioned elastic strands along the longitudinal edges, forexample. When contracted the elastic strands form gathers of material.Leg cuffs, as opposed to barrier cuffs that are generally disposedinboard, that is, toward the center of the diaper and away from thelongitudinal edges of the diaper chassis, can include a portion of thelongitudinal edge of the diaper chassis. This longitudinal edge is oftenunsightly, that is, it appears as an unfinished edge that may have arather rough appearance. The appearance is important, as consumerperception of softness and comfort are significant considerations forcommercial success in the disposable absorbent article field.

[0006] In addition to the appearance of leg cuffs in absorbent articles,leg cuffs are relatively costly. In particular, for elasticized legcuffs, there is a need for elastic in the portion of the longitudinaledge of the chassis that defines the leg opening. However, due to thenature of commercial production of disposable absorbent garments, it isnot feasible to apply discrete segments of a material, such as a patchor a strand of elastic material, to a discrete portion of the diaperchassis. For example, it is very difficult to cut a strand of elastic toa length shorter than the long dimension of the chassis and affix it ina predetermined location on the chassis, all at high speed in arepeating manner. For this reason, leg cuff (as well as barrier cuff)elastics are often applied as continuous strands that extend the entirelength of the long dimension of the chassis, generally near thelongitudinal edges. However, the extra elastic, beyond the portion ofthe longitudinal edges that define the leg opening, is non-value-addedmaterial content.

[0007] Accordingly, it would be desirable to have a disposable absorbentarticle having a leg cuff that has a finished, comfortable appearance.

[0008] Additionally, it would be desirable to have a method for making aleg cuff having a finished appearance in a commercially viable manner.

[0009] Further, it would be desirable to have a disposable absorbentarticle with a leg cuff having a finished appearance, with the finishedappearance limited to the portion of the longitudinal edge of thechassis that defines a leg opening when worn.

[0010] Finally, it would be desirable to have a commercially-viablemethod of making a disposable absorbent article with a leg cuff having afinished appearance, with the finished appearance limited to the portionof the longitudinal edge of the chassis that defines a leg opening whenworn.

BRIEF SUMMARY OF THE INVENTION

[0011] In accordance with a first aspect of the present invention, adisposable diaper is provided. The disposable diaper comprises atopsheet, a backsheet, and an absorbent core disposed between thetopsheet and the backsheet, the topsheet and the backsheet defining aperiphery and longitudinal edges, portions of the longitudinal edgesdefining leg openings when the disposable diaper is worn, the disposablediaper comprising on each longitudinal edge a discrete edge seal foldedabout and joined to the longitudinal edges at least at the portions ofthe longitudinal edges defining leg openings when the disposable diaperis worn, wherein the discrete edge seals do not extend the entire lengthof the longitudinal edge of the disposable diaper.

[0012] In accordance with a second aspect of the present invention,apparatus for affixing a discrete edge seal onto a portion of alongitudinal edge of a continuous web is provided. The apparatus havingan axis of rotation, and comprises

[0013] a) a first web surface disposed at a first radial distance fromthe axis;

[0014] b) an edge seal folder comprising a second web surface disposedat a second radial distance from the axis, the second radial distancebeing variable between a first minimum distance and a second maximumdistance, wherein at the second maximum distance the second radialdistance is substantially equal to the first radial distance;

[0015] c) the edge seal folder adapted to receive edge seal material onthe second web surface at the first minimum distance and to fold andaffix the edge seal material as a discrete edge seal onto a portion ofthe longitudinal edge of the continuous web at the second maximumdistance.

[0016] In accordance with a third aspect of the present invention, amethod of affixing a discrete edge seal onto a predetermined portion ofa longitudinal edge of a continuous web is provided. The methodcomprises the steps of:

[0017] a) providing the continuous web;

[0018] b) providing a continuous web of edge seal material;

[0019] c) providing an edge seal folder that is translatable radiallyoutward with respect to an axis of rotation between a first minimumdistance and a second maximum distance;

[0020] d) receiving a portion of the continuous web of edge sealmaterial upon a surface of the edge seal folder;

[0021] e) applying adhesive to either of the portion of the continuousweb of edge seal material or the continuous web in a predeterminedlocation;

[0022] f) cutting off the portion of the continuous web of edge sealmaterial from the continuous web of edge seal material;

[0023] g) retaining the portion from the continuous web of edge sealmaterial upon the surface of the edge seal folder;

[0024] h) translating the edge seal folder from the first minimumdistance to the second maximum distance;

[0025] i) folding the portion of the continuous web of edge sealmaterial about the predetermined portion of the longitudinal edge of thecontinuous web; and

[0026] j) joining the portion of the continuous web of edge sealmaterial to the predetermined portion of the longitudinal edge of thecontinuous web.

[0027] All patents, articles, documents, and other materials cited are,in relevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

[0028] All measurements are in SI units, unless otherwise specified.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] While the specification concludes with claims pointing out anddistinctly claiming the present invention, it is believed the same willbe better understood by the following drawings taken in conjunction withthe accompanying specification wherein like components are given thesame reference number.

[0030]FIG. 1 is a perspective view of one embodiment of an absorbentarticle of the present invention.

[0031]FIG. 2 is a cross-sectional view of a portion of an edge sealportion of the absorbent article shown in FIG. 1.

[0032]FIG. 3 is a cross-sectional view of an alternative embodiment ofan edge seal portion of an absorbent article.

[0033]FIG. 4 is a perspective schematic representation of an apparatusof the present invention for making an absorbent article of the presentinvention.

[0034]FIG. 5 is a schematic representation of an apparatus of thepresent invention for making an absorbent article of the presentinvention.

[0035]FIG. 6 is a schematic cross-sectional view of an apparatus of thepresent invention.

[0036]FIG. 7 is a perspective view of one embodiment of an edge sealfolder of the present invention.

[0037]FIG. 8 is a profile schematic representation of an edge sealfolder of the present invention.

[0038]FIG. 9 is a perspective view of an alternative embodiment of anedge seal folder of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0039] As used herein, the term “absorbent article” refers to devicesthat absorb and contain body exudates, and more specifically, refers todevices that are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term “disposable” is used herein to describe absorbentarticles that generally are not intended to be laundered or otherwiserestored or reused as an absorbent article (i.e., they are intended tobe discarded after a single use).

[0040] As used herein, the term “disposed” is used to mean that anelement(s) of the diaper is formed (joined and positioned) in aparticular place or position as a unitary structure with other elementsof the diaper or as a separate element joined to another element of thediaper. As used herein, the term “joined” encompasses configurationswhereby an element is directly secured to another element by affixingthe element directly to the other element, and configurations whereby anelement is indirectly secured to another element by affixing the elementto intermediate member(s) that in turn are affixed to the other element.

[0041] As used herein, the term “elastic” or “elastomeric” refers to anymaterial which, upon application of a biasing force, is stretchable,that is, elongatable, at least about 60 percent (i.e., to a stretched,biased length, which is at least about 160 percent of its relaxedunbiased length), and which, will recover at least 55 percent of itselongation upon release of the stretching, elongation force. Ahypothetical example would be a one (1.0) cm sample of a material whichis elongatable to at least 1.60 cm, and which, upon being elongated to1.60 cm and released, will recover to a length of not more than 1.27 cm.Many elastic materials may be elongated by more than 60 percent (i.e.,much more than 160 percent of their relaxed length), for example,elongated 100 percent or more, and many of these materials will recoverto substantially their initial relaxed length, for example, to within105 percent of their initial relaxed length, upon release of the stretchforce. Such materials are referred to herein as “highly elastic”.

[0042] As used herein, the term “nonelastic” refers to any material thatdoes not fall within the definition of “elastic” (or “elastomeric”) or“highly elastic” above.

[0043] As used herein, the term “extensible” refers to any materialthat, upon application of a biasing force, is elongatable, at leastabout 50% without offering a significant resistance force (less than 10g/cm) or experiencing catastrophic failure. Catastrophic failureincludes substantial tearing, fracturing, rupturing, or other failure intension such that, if tested in a standard tensile tester, the failurewould result in a sudden significant reduction in measured tensileforce. As used herein, the term “highly extensible” refers to anymaterial which, upon application of a biasing force, is elongatable, atleast about 70%, more preferably at least about 100%, and even morepreferably about 120% without offering a significant resistance force(less than 10 g/cm) or experiencing catastrophic failure.

[0044] A “unitary” absorbent article refers to absorbent articles thatare formed of separate parts united together to form a coordinatedentity so that they do not require separate manipulative parts like aseparate holder and liner. A preferred embodiment of an absorbentarticle of the present invention is the unitary disposable absorbentarticle, diaper 20, shown in FIG. 1. As used herein, the term “diaper”refers to an absorbent article generally worn by infants and incontinentpersons about the lower torso, and includes both tape-type diapers(diapers having adhesive tapes, hook and loop fasteners, and the like,that fastened about the waist of the wearer), and pull-on pant-typediapers. The present invention is also applicable to other absorbentarticles such as incontinence briefs, incontinence undergarments,absorbent inserts, diaper holders and liners, and the like.

[0045] As used herein, the term “discrete edge seal” or “edge seal”refer to a discrete elongate element that wraps about a portion of alongitudinal edge of a diaper, thus “sealing” that portion of the “edge”of the diaper. Edge seals as described herein provide a soft, finishedappearance to the portions of the longitudinal edge of a diaper thatform the leg openings when worn.

[0046]FIG. 1 is a plan view of the diaper 20 of the present invention ina flat-out state with portions of the structure being cut away to moreclearly show the construction of the diaper 20. The portion of thediaper 20 that faces the wearer is oriented towards the viewer. As shownin FIG. 1, the diaper 20 preferably comprises a liquid pervious topsheet24; a liquid impervious backsheet 26, an absorbent core 28 which ispreferably positioned between at least a portion of the topsheet 24 andthe backsheet 26; side panels 30; elasticized leg cuffs 32; and anelastic waist feature 34.

[0047] Diaper 20 is shown in FIG. 1 to have a first waist region 36, asecond waist region 38 opposed to the first waist region 36 and a crotchregion 37 located between the first waist region and the second waistregion 38. The periphery of the diaper 20 is defined by the outer edgesof the diaper 20 in which the longitudinal edges 50 are orientedgenerally parallel to the longitudinal centerline 70 of the diaper 20and the end edges 52 run between the longitudinal edges 50 generallyparallel to the transverse centerline 72 of the diaper 20. However, forbetter fit, longitudinal edges 50 are preferably curved to produce an“hourglass” shape diaper when viewed in the flat-out configuration ofFIG. 1. The chassis 22 of the diaper 20 comprises the main body of thediaper 20. The chassis 22 comprises at least the topsheet 24 and thebacksheet 26.

[0048] For tape-type diapers, that is, diapers intended to be fastenedabout the wearer by use of an adhesive tape or releasable mechanicalfastener, the diaper 20 can have a fastening system generally designated40, as is commonly known in the art. Once fastened upon the wearer,portions of longitudinal edge 50 define leg openings. For pant-typediapers, first waist region 36 is joined by suitable means to the secondwaist region 38, as is commonly known in the art, to make a pant-typegarment having leg openings defined by the non-joined portions oflongitudinal edges 50. Joining of the waist regions can be by thermalbonding, adhesive bonding, or ultrasonic bonding, for example.

[0049] While the topsheet 24, the backsheet 26, and the absorbent core26 may be assembled in a variety of well-known configurations, preferredtape-diaper configurations are described generally in U.S. Pat. No.3,860,003 entitled “Contractible Side Portions for Disposable Diaper”which issued to Kenneth B. Buell on Jan. 14, 1975; U.S. Pat. No.5,151,092 issued to Buell on Sep. 9, 1992; and U.S. Pat. No. 5,221,274issued to Buell on Jun. 22, 1993; and U.S. Pat. No. 5,554,145 entitled“Absorbent Article With Multiple Zone Structural Elastic-Like Film WebExtensible Waist Feature” which issued to Roe et al. on Sep. 10, 1996;U.S. Pat. No. 5,569,234 entitled “Disposable Pull-On Pant” which issuedto Buell et al. on Oct. 29, 1996; and U.S. Pat. No. 5,580,411 entitled“Zero Scrap Method For Manufacturing Side Panels For Absorbent Articles”which issued to Nease et al. on Dec. 3, 1996. Preferred pant-typediapers and methods for making suitable side seams are disclosed in U.S.Pat. No. 5,569,234 issued to Buell, et al. on Oct. 29, 1996, U.S. Pat.No. 5,607,537 issued to Johnson et al. on Mar. 4, 1997, U.S. Pat. No.5,662,638 issued to Johnson et al. on Sep. 2, 1997, and U.S. Pat. No.5,685,874 issued to Buell et al. on Nov. 11, 1997. Preferable seams aredisclosed in European Patent Application No. 96118654.1 titled “ThermalJoining of Webs” filed on Nov. 21, 1996 (Christoph J. Schmitz).

[0050] The backsheet 26 is generally that portion of the diaper 20positioned adjacent the garment facing surface 45 of the absorbent core28 which prevents the exudates absorbed and contained therein fromsoiling articles which may contact the diaper 20, such as bed sheets andundergarments. In preferred embodiments, the backsheet 26 is imperviousto liquids (e.g., urine) and comprises a thin plastic film such as athermoplastic film having a thickness of about 0.012 mm (0.5 mil) toabout 0.051 mm (2.0 mils). Suitable backsheet films include thosemanufactured by Tredegar Industries Inc. of Terre Haute, Ind. and soldunder the trade names XI 5306, X10962 and X10964. Other suitablebacksheet materials may include breathable materials that permit vaporsto escape from the diaper 20 while still preventing exudates frompassing through the backsheet 26. Exemplary breathable materials mayinclude materials such as woven webs, nonwoven webs, composite materialssuch as film-coated nonwoven webs, and micro porous films such asmanufactured by Mitsui Toatsu Co., of Japan under the designation ESPOIRNO and by EXXON Chemical Co., of Bay City, Tex., under the designationEXXAIRE. Suitable breathable composite materials comprising polymerblends are available from Clopay Corporation, Cincinnati, Ohio under thename HYTREL® blend P18-3097. Such breathable composite materials aredescribed in greater detail in PCT Application No. WO 95/16746,published on Jun. 22, 1995 in the name of E. I. DuPont and copendingU.S. patent application Ser. No. 08/744,487, filed on Nov. 6, 1996 inthe name of Curro. Other breathable backsheets including nonwoven websand apertured formed films are described in U.S. Pat. No. 5,571,096issued to Dobrin et al. on Nov. 5, 1996.

[0051] The backsheet 26, or any portion thereof, may be elasticallyextensible in one or more directions. In one embodiment, the backsheet26 may comprise a structural elastic-like film (“SELF”) web. Astructural elastic-like film web is an extensible material that exhibitsan elastic-like behavior in the direction of elongation without the useof added elastic materials. SELF webs suitable for the present inventionare more completely described in U.S. Pat. No. 5,518,801 entitled WebMaterials Exhibiting Elastic-Like Behavior, which issued to Chappell, etal. on May 21, 1996.

[0052] The backsheet 26 may be joined to the topsheet 24, the absorbentcore 28 or any other element of the diaper 20 by any attachment meansknown in the art. For example, hot melt adhesives applied about theportions of the peripheral edges can be sufficient to join the topsheetand backsheet to one another.

[0053] The topsheet 24 is preferably positioned adjacent the bodysurface 47 of the absorbent core 28 and may be joined thereto and/or tothe backsheet 26 by any attachment means known in the art. The topsheet24 is preferably compliant, soft feeling, and non-irritating to thewearer's skin. Further, at least a portion of the topsheet 24 is liquidpervious, permitting liquid to readily penetrate through its thickness.A suitable topsheet 24 may be manufactured from a wide range ofmaterials, such as porous foams; reticulated foams; apertured plasticfilms; or woven or nonwoven webs of natural fibers (e.g., wood or cottonfibers), synthetic fibers (e.g., polyester or polypropylene fibers), ora combination of natural and synthetic fibers.

[0054] Any portion of the topsheet 24 may be coated with a lotion as isknown in the art. Examples of suitable lotions include those describedin U.S. Pat. Nos. 5,607,760 entitled “Disposable Absorbent ArticleHaving A Lotioned Topsheet Containing an Emollient and a PolyolPolyester Immobilizing Agent” which issued to Roe on Mar. 4,1997; U.S.Pat. No. 5,609,587 entitled “Diaper Having A Lotion Topsheet ComprisingA Liquid Polyol Polyester Emollient And An Immobilizing Agent” whichissued to Roe on Mar. 11, 1997; U.S. Pat. No. 5,635,191 entitled “DiaperHaving A Lotioned Topsheet Containing A Polysiloxane Emollient” whichissued to Roe et al. on Jun. 3, 1997; and U.S. Pat. No. 5,643,588entitled “Diaper Having A Lotioned Topsheet” which issued to Roe et al.on Jul. 1, 1997.

[0055] The absorbent core 28 may comprise any absorbent material whichis generally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. The absorbent core 28 may be manufacturedin a wide variety of sizes and shapes (e.g., rectangular, hourglass,“T”-shaped, asymmetric, etc.) and may comprise a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp, which is generallyreferred to as airfelt. Examples of other suitable absorbent materialsinclude creped cellulose wadding; melt-blown polymers, including coform;chemically stiffened, modified or cross-linked cellulosic fibers;tissue, including tissue wraps and tissue laminates; absorbent foams;absorbent sponges; superabsorbent polymers; absorbent gelling materials;or any other known absorbent material or combinations of materials.

[0056] The diaper 20 can also comprise at least one elastic waistfeature 34 that helps to provide improved fit and containment. Theelastic waist feature 34 is generally intended to elastically expand andcontract to dynamically fit the wearer's waist. The elastic waistfeature 34 preferably extends at least longitudinally outwardly from atleast one waist edge 62 of the absorbent core 28 and generally forms atleast a portion of the end edge 52 of the diaper 20. Disposable diapersare often constructed so as to have two elastic waist features, onepositioned in the first waist region 36 and one positioned in the secondwaist region 38. Further, while the elastic waist feature 34 or any ofits constituent elements may comprise one or more separate elementsaffixed to the diaper 20, the elastic waist feature 34 may beconstructed as an extension of other elements of the diaper 20, such asthe backsheet 26, the topsheet 24, or both the backsheet 26 and thetopsheet 24. The elastic waist feature 34 may be constructed in a numberof different configurations including those described in U.S. Pat. No.4,515,595 issued to Kievit et al. on May 7, 1985; U.S. Pat. No.4,710,189 issued to Lash on Dec. 1, 1987; U.S. Pat. No. 5,151,092 issuedto Buell on Sept. 9, 1992; and U.S. Pat. No. 5,221,274 issued to Buellon Jun. 22, 1993. Other suitable waist configurations may includewaistcap features such as those described in U.S. Pat. No. 5,026,364issued to Robertson on Jun. 25, 1991 and U.S. Pat. No. 4,816,025 issuedto Foreman on Mar. 28, 1989.

[0057] The diaper 20 may also include a fastening system 40. Inparticular, tape-type diapers have a fastening system. The fasteningsystem 40 preferably maintains the first waist region 36 and the secondwaist region 38 in an overlapping configuration so as to provide tensionabout the circumference of the waist opening of the diaper 20 to holdthe diaper 20 on the wearer. The fastening system 40 preferablycomprises tape tabs and/or hook and loop fastening components, althoughany fastening means known in the art is generally acceptable.

[0058] In pant-type diapers, opposing sides, i.e., longitudinal edgeportions of first waist region 36 and second waist region 38, of thegarment are seamed or welded to form a pant, as is known in the art.This allows the article to be used as a pull-on type diaper, such as atraining pant.

[0059] The diaper 20 can also comprise side panels 30. The side panels30 may be elastic or extensible to provide a more comfortable andcontouring fit by initially conformably fitting the diaper 20 to thewearer and sustaining this fit throughout the time of wear well pastwhen the diaper 20 has been loaded with exudates since the elasticizedside panels 30 allow the sides of the diaper 20 to expand and contract.The side panels 30 may be constructed in any suitable configurations asknown in the art. Examples of diapers with elasticized side panels aredisclosed in U.S. Pat. No. 4,857,067, entitled Disposable Diaper HavingShirred Ears issued to Wood, et al. on Aug. 15, 1989; U.S. Pat. No.4,381,781 issued to Sciaraffa, et al. on May 3, 1983; U.S. Pat. No.4,938,753 issued to Van Gompel, et al. on Jul. 3, 1990; the hereinbefore referenced U.S. Pat. No. 5,151,092 issued to Buell on Sep. 9,1992; and U.S. Pat. No. 5,221,274 issued to Buell on Jun. 22, 1993; U.S.Pat. No. 5,669,897 issued to LaVon, et al. on Sep. 23, 1997 entitledAbsorbent Articles Providing Sustained Dynamic Fit; U.S. patentapplication Ser. No. 08/155,048 entitled Absorbent Article WithMulti-Directional Extensible Side Panels filed Nov. 19, 1993 in thenames of Robles, et al.

[0060] The diaper 20 preferably further includes leg cuffs 32 whichprovide improved containment of liquids and other body exudates. Legcuffs may also be referred to as legbands, side flaps, barrier cuffs, orelastic cuffs. U.S. Pat. No. 3,860,003 describes a disposable diaperwhich provides a contractible leg opening having a side flap and one ormore elastic members to provide an elasticized leg cuff(a gasketingcuff). U.S. Pat. Nos. 4,808,178 and 4,909,803 issued to Aziz et al. onFeb. 28, 1989 and Mar. 20, 1990, respectively, describe disposablediapers having “standup” elasticized flaps (barrier cuffs) that improvethe containment of the leg regions. U.S. Pat. Nos. 4,695,278 and4,795,454 issued to Lawson on Sep. 22, 1987 and to Dragoo on Jan. 3,1989, respectively, describe disposable diapers having dual cuffs,including gasketing cuffs and barrier cuffs.

[0061] In prior art diapers longitudinal edges 50 were left unfinished,that is, the edges of the component webs, such as the topsheet 24 andbacksheet 26, were left exposed. Although functional, this configurationleaves the diaper with an unfinished look. Attempts to make the diapermore garment-like by finishing the longitudinal edges 50 in aneconomical manner have thus far proved unsatisfactory. Edge folding andseaming, for example, particularly on a curved “hourglass” shaped edge,requires complex equipment, and, at best, would only slightly improvethe appearance of the edge 50. The addition of separate, discreteportions of edge-finishing materials involves the cutting and accurateplacement of materials on high-speed equipment, which, until the presentinvention, has proved impractical as well.

[0062] The article of the present invention is an improved diaper havinga finished edge cuff. The finished edge cuff comprises an edge seal 60that is joined to a portion of longitudinal edge 50. Edge seal 60preferably comprises a soft, pliable, non-irritating nonwoven material,and is discrete. Edge seal can be extensible, and can be elastic orhighly elastic, or rendered elastic or highly elastic. In general,materials described as suitable for the topsheet 24 are also suitablematerials for use as the edge seal 60. By discrete is meant that theedge seal 60 is not applied as a continuous member to the entire lengthof longitudinal edge 50 during diaper manufacture, thereby extending theentire longitudinal length of the diaper 20. Therefore, one advantage ofthe present invention is edge seal 60 need only be joined aboutlongitudinal edge 50 along portions defining the leg opening when diaper20 is worn. This represents a significant material cost savings.Therefore, each edge seal 60 comprises a discrete edge seal 60 that isjoined to the diaper 20 in a folded configuration such that it wraps, orencloses, at least a portion of the longitudinal edge 50 of the diaper20 to give the leg opening of diaper 20 a finished, seamed, appearance.Preferably each edge seal 60 has dimensions such that when the diaper 20is worn, the edge seal 60 completely encircles the portion oflongitudinal edge that defines the leg opening.

[0063] Accordingly, in one embodiment, the present invention can bedescribed as a disposable diaper (tape-type or pant-type) comprising atopsheet, a backsheet, and an absorbent core disposed between thetopsheet and said backsheet, the topsheet and backsheet defining aperiphery and longitudinal edges, portions of the longitudinal edgesdefining leg openings when the diaper is worn, and an edge seal foldedabout and joined to the longitudinal edges at least at the portionsdefining leg openings when the diaper is worn. In one embodiment theedge seals are joined about the longitudinal edges only at the portionsdefining the leg openings. In one embodiment the edge seals do notextend the entire length of the longitudinal edge of the diaper.

[0064] The fold of the edge seal 60 about the edge of the diaper can bedescribed as a C-fold, or an “edge wrap” and one embodiment is shownmore clearly in the cross sectional view of FIG. 2. As shown in FIG. 2,edge seal 60 wraps completely around longitudinal edge 50, such thatlongitudinal edge 50 is no longer exposed at the edge-sealed portions.Edge seal 60 can be joined in ways known in the art for bonding nonwovenwebs, such as by adhesive bonding. For example, hot melt adhesive 66 canbe applied to portions of topsheet 24, backsheet 26, and/or edge seal 60prior to placement of edge seal 60 in the folded configuration aboutlongitudinal edge 50. If necessary, heat and pressure can be applied aswell to ensure sufficient joining of the edge seal 60.

[0065] Edge seal 60 can be longitudinally elastic. That is, in oneembodiment, edge seal 60 comprises an elastomeric material and edge seal60 is affixed to longitudinal edge 50 while in a stretched, elongatedcondition. Once tension is released from edge seal 60, it can thencontract longitudinally to form gathers along the leg opening of thediaper. The gathers give the diaper leg opening a soft, plush look andfeel. Elastomeric properties can be achieved by the use of anelastomeric nonwoven material for example, or by the addition of elasticstrands to edge seal 60.

[0066] As shown in FIG. 3, a portion of edge seal 60 can be extended toform an integrated barrier cuff portion 61, which can replace, orcomplement elasticized leg cuffs 32. Barrier cuff portion 61 is joinedto edge seal 60 at a proximal portion 65, and overlaps topsheet 24, butis unattached to topsheet 24 at a distal portion 67. In a preferredembodiment, distal portion 67 comprises an elastic component such aselastic strand 64, or other elastic components as are known in the artof elasticized leg cuffs including barrier leg cuffs. Thus, when in use,elasticized distal portion 67 can “stand up” to form a barrier cuff, asis known in the art of barrier cuffs.

APPARATUS AND METHOD OF MAKING

[0067] The edge seals 60 can be affixed to the absorbent article byhand, such as by gluing in position while the article is in a flat,extended configuration. However, such a process is time and laborintensive, and is not feasible for commercial production of absorbentarticles. Therefore, the apparatus and method disclosed herein ispreferred for commercially viable production of absorbent articleshaving an edge seal 60, and in particular a discrete edge seal 60 (i.e.,an edge seal 60 that not extend the entire length of the longitudinaledge 50 of the diaper).

[0068]FIG. 4 shows a schematic representation of an apparatus 100 formaking an absorbent article having an edge seal 60. To process absorbentarticles in a commercially viable manner, the apparatus is designed toprocess materials supplied from continuous webs. However, since in apreferred embodiment the edge seal 60 is affixed as a discrete edge sealsegment (i.e., not a continuous web), the apparatus 100 is designed toprocess an edge seal web material supplied from a continuous web toproduce a discrete edge seal 60 affixed at spaced apart locations toportions of the longitudinal edge of a continuous web of material thateventually will comprise the chassis of a diaper.

[0069] In a commercially viable embodiment edge seals 60 are affixed toboth longitudinal edges 50 of diaper 20 simultaneously. Therefore,although the apparatus and process are described below with respect toone edge seal web 150 forming one edge seal 60, it should be appreciatedthat the apparatus 100 preferably is configured substantiallysymmetrically, such that two continuous edge seal webs 150 aresimultaneously supplied to and processed by the apparatus 100 shown inFIG. 4. Therefore, the description of the apparatus with respect to FIG.4, for example, is directed to the operation of the apparatus withrespect to the side of the apparatus visible in FIG. 4. But theapparatus 100 is two-sided, such that both webs 150 shown in FIG. 4 aresimultaneously processed into edge seals 60 of the finished article.

[0070] To accomplish the task of applying edge seal 60 in a spacedrelationship to a continuous web of material being processed at highspeed, the apparatus 100 is a rotary apparatus wherein certain operativesurfaces rotate about a common axis 110 in a continuous, repeatingprocess, as described herein. In general, the apparatus 100 works on theprinciple of differential surface path lengths of circumferential (orperipheral) surfaces. That is, as the radial distance from the axis 110increases, the circumference of a circle associated with the radialdistance also increases. The apparatus 100 has at least two operativesurfaces, referred to a “web surfaces” herein because the surfaces aredesigned to handle web materials in a continuous cyclic process.

[0071] A first web surface 120 is disposed at a first radial distance D1from axis 110. The distance D1 can be, as shown in FIG. 4, a fixeddistance (i.e., first web surface 120 defines a circular configurationwhen viewed in profile, that is, parallel to axis 110), but can be avariable distance (i.e., first web surface 120 defines a polygonalconfiguration when viewed in profile, that is, parallel to axis 110).First web surface 120 is preferably continuous, such as thecircumferential surface of a right circular cylinder (D1 is fixed andconstant) or the peripheral surface of a right polygonal cylinder (D1varies from a minimum measured to the center of each polygonal segmentto a maximum at the vertex of the angle formed by adjacent polygonalsegments). Regardless of the particular configuration of first websurface 120, in a preferred embodiment any given point on first websurface 120 remains at a constant distance D1 from axis 110 during theoperation of apparatus 100.

[0072] First web surface 120 has a longitudinal axis L1 and a transverseaxis T1 perpendicular to longitudinal axis L1. First web surface 120also has a width W1 measured parallel to the transverse axis T1. WidthW1 can be constant or varying.

[0073] A portion of first web surface 120 supports a continuous web 140having a longitudinal axis L2 oriented in the machine direction MD, anda transverse axis T2 perpendicular to longitudinal axis L2. Continuousweb 140 also has a width W2 measured in the cross-direction CD, parallelto the transverse axis T2 (perpendicular to the MD), and width W2 can beconstant or varying. In operation, continuous web 140 can be guidedadjacent to, and preferably in contact with, a portion of first websurface 120, which is designed to support web 140 during the portion ofthe process in which portions of edge seal web material 150 are foldedand joined thereto to become edge seals 60 as discussed more fullybelow. In a preferred embodiment, during processing as described herein,the longitudinal axis L2 of web 140 is aligned parallel and adjacent tolongitudinal axis L1 of first web surface 120.

[0074] Continuous web 140 can be a portion of the absorbent article inprocess. That is, continuous web 140 can be a laminate web comprisingmultiple layers of component materials, such as diaper chassismaterials, in the process of being assembled into a finished absorbentarticle, as is known in the art of commercial disposable diapermanufacture. For example, continuous web 140 can be a liquid impermeablebacksheet material, or a nonwoven topsheet material. In a preferredembodiment, continuous web 140 is a laminate comprising a continuous webof backsheet and topsheet material joined together as is known in theart of diaper manufacture. In a preferred embodiment, as shown onincoming continuous web 140A in FIG. 4, portions of longitudinal edgesof continuous web 140 are cut, or “notched” to form curvilinear notchedportions that form an “hourglass” shaped chassis in the finishedarticle. A plurality of discontinuous and spaced apart absorbent coreelements (not shown in FIG. 4) can be disposed between the continuousweb of backshect and topsheet materials.

[0075] Continuous web 140 can be guided adjacent to web surface 120 byany suitable means. In one embodiment, as shown in FIG. 4, guide rollers102 are operatively positioned such that continuous web 140 is urgedagainst a portion of web surface 120, which correspondingly supportscontinuous web 140 for a portion that can be described as a defined arclength of first web surface 120. If first web surface 120 is not at aconstant distance from axis 110, i.e., the web surface 120 is notcircular in shape when viewed parallel to axis 110, then guide rollers102 can be correspondingly operatively positioned. For example, in oneembodiment, each guide roller 102 can itself be spaced a distance fromaxis 110 equal to or greater than the maximum distance D1. In anotherembodiment guide rollers 102 can be biased, such as by spring loading,to provide constant pressure against web surface 120 even as its radialdistance from axis 110 changes.

[0076] In operation, continuous web 140 is guided in the direction shownby the arrows associated therewith, as the apparatus 100 rotates aboutaxis 110 in the direction shown by the arrows associated therewith(counter-clockwise as viewed in FIG. 4). The linear, i.e., tangentialspeed of web surface 120 is essentially the same as, and preferablyexactly the same as, the linear speed of continuous web 140, such thatduring the portion of the process in which continuous web 140 isdisposed adjacent first web surface 120, there is no relative motionbetween continuous web 140 and first web surface 120.

[0077] In one embodiment, first web surface 120 can have a varying widthW1 defining spaced apart notches 122. In a preferred embodiment, thevarying width W1 defines a plurality of regularly spaced, opposingnotches, as shown in FIG. 4. In operation of a preferred embodiment ofapparatus 100 the notches correspond to corresponding notched portionsof continuous web 140 to which edge seals 60 are applied. That is,notched portions of continuous web 140 line up adjacent to respectivenotched portions of first web surface 120 when continuous web 140 isdisposed adjacent to first web surface 120. Thus, edge seals 60 can bediscrete members that provide a finished edge to the leg openingsdefined by the concave portions of an hourglass-shaped diaper chassis.However, it is not necessary that first web surface 120 exhibit suchnotches. In one embodiment of apparatus 100, for example, portions ofthe width W2 of web 140 are sufficiently greater than a constant widthW1 of web surface 120, so that the edge seals 60 can be affixed to suchportions (i.e., overhanging edges of web 140).

[0078] Edge seals 60 are discrete elements joined to a portion of eachlongitudinal edge 50 of diaper 20. However, in a commercially viableprocess, it is necessary that edge seals 60 be processed from acontinuous web material preferably supplied as roll stock or festoonedfor substantially continuous processing as a web. To facilitate webjoining of a relatively short discrete member to a relatively longercontinuous member, the apparatus 100 of the present invention has asecond web surface 130 that is at a second radial distance D2 from axis110. Second web surface 130 can be comprised of a plurality of edge sealfolders 132, each of which are preferably identical to one another. Eachedge seal folder 132 is designed to convey a discrete edge seal portion152, which, once folded and joined to continuous web 140 becomes edgeseal 60. Thus, edge seal folders 132 receive a continuous web of edgeseal material 150 and subsequently facilitate control of edge sealmaterial 150 as it is cut to make a discrete edge seal portion 152having a predetermined length and which is translated to a predeterminedposition and folded and joined about a predetermined portion ofcontinuous web 140 to form an edge seal 60 of the present invention. Thepredetermined locations are spaced apart, and correspond to the portionof the chassis longitudinal edges 50 that define at least portions of aleg opening when the finished garment is worn.

[0079] Each edge seal folder 132 defines a portion of second web surface130 that can be substantially flat in profile (i.e., as viewed parallelto axis 110), or each can define a second web surface 130 that makes anarc segment in profile as shown in FIG. 4. The actual profile of edgeseal folders 132 preferably matches the profile of first web surface120. That is, the arc radius defined by the second web surface 130 ofedge seal folders 132 is preferably identical to the arc radius definedby the first web surface 120.

[0080] Each edge seal folder 132 occupies a position at a variabledistance D2 from axis 110. Each edge seal folder 132 can translate,i.e., move, from a first position that is a minimum radial distanceD2min from axis 110 to a second position that is a maximum radialdistance D2max from axis 110, as shown in FIG. 4. Three edge sealfolders 132 shown as segments 132A in FIGS. 4 and 5 are at minimumradial distance D2min. In the embodiment shown in FIG. 4, the apparatus100 rotates as shown by the arrow associated therewith (i.e., in acounter-clockwise manner as viewed in FIG. 4), and as it rotates, edgeseal folders 132 are translated from minimum radial distance D2min in adirection away from axis 110 until they reach a maximum radial distanceD2max. An edge seal folder 132 in this position is shown as segment 132Din FIGS. 4 and 5.

[0081] In addition to translating in a direction radially outwardly from(or inwardly toward) axis 110, edge seal folders 132 preferablytranslate in a direction parallel to axis 110. That is, as can be seenbest in the cross section of FIG. 6, edge seal folders 132 receivecontinuous edge seal web 150 at a maximum distance from line of symmetry112, and move toward the line of symmetry 112 when moving away from axis110. In this manner, both continuous webs 140 and 150 can be processedfrom their respective supply packages generally to one another.

[0082] In the embodiment shown in FIG. 4, when segments 132 are at themaximum radial distance D2max, the second web surface 130 and first websurface 120 are at a substantially equal radial distance from axis 110.By “substantially equal” is meant that, for practical purposes, the twosurfaces are the same distance from axis 110, but the term is not meantto convey mathematical exact equality. In some processes it may bedesirable to have a difference in radial distance between the first andsecond web surfaces when a edge seal folders 132 are at the maximumradial distance D2max.

[0083] Edge seal folders 132 are translated from a first position, atwhich position edge seal web 150 is operatively disposed thereon, to asecond position, at which position the edge seal portion 152 is foldedand affixed to the continuous web 140, that is, to what will eventuallybe the longitudinal edges of a disposable diaper, and back to the firstposition in a continuous, repeating process. By “operatively disposed”thereon is meant that the edge seal web 150 is received by and disposedon edge seal folder 132 in a generally flattened, extended position andorientation with respect to the edge seal folder 132, such that onceedge seal web 150 is cut into discrete edge seal portion 152 and edgeseal folder 132 begins translating it to its respective second position,the edge seal portion 152 is accurately positioned for folding andaffixing to the continuous web 140 to form a completed edge seal 60.

[0084] The apparatus and process are now discussed in more detail withreference to a particular method of operation with respect to FIGS. 4, 5and 6. FIG. 5 is a schematic representation of the apparatus 100 asviewed parallel to axis 110. FIG. 6 is a cross-sectional view ofapparatus 100.

[0085] As one can see with reference to FIGS. 4 and 5, the apparatus 100permits continuous webs 140, 150 to be processed into an article of thepresent invention having discrete (i.e., non-continuously applied) edgeseals 60. That is, although each edge seal could be supplied as discrete“patches” or sheets of material, and applied by hand or by automaticplacement equipment onto the second web surface 130 of each edge sealfolder 132 when it is at its first position D2min, in a preferredembodiment, edge seal web material 150 is supplied as a continuous webof material, such as a relatively narrow strip of nonwoven material.While the general principle of operation can be practiced in variousways, the following description is intended to be a nonlimiting exampleof a currently preferred apparatus.

[0086] Apparatus 100 comprises a stationary portion 200 and a rotatingportion 300. Stationary portion 200 comprises a mounting shaft 210 thatis parallel to, and coaxial with axis 110 of apparatus 100. Affixed toshaft 210 is cam plate 212. Cam plate 212 comprises a cam track 220,which itself comprises an inner cam track surface 222 and an outer camtrack surface 224. Rotating portion 300 can be mounted on suitablebearings 310, such as ball bearings, and rotates about shaft 210. Firstsurface 120 forms an outer periphery of rotating portion 300. Rotatingportion 300 has a plurality of slots 320 (shown in FIG. 4) and guides330 (shown in FIG. 7) that serve to facilitate linear motion of edgeseal folders 132 in a direction radially outwardly from axis 110. Guides330 can be linear slide bearings, for example. Each edge seal folder 132is operatively attached through a respective slot 320 to a pair of camfollowers 131 disposed in operative relationship within cam track 220.Therefore, as rotating portion 300 is rotated, each edge seal folder 132is forced by the cam followers 131 in cam track 220 to follow a complexpath, rotationally about and away from axis 110 and toward plane ofsymmetry 112, or vice-versa, depending on where the edge seal folder isin the cycle of operation. Starting from the position identified as132A, the rotation of rotating portion 300 forces edge seal folders 132to translate relative to axis 110, which has the effect of movingportions of second web surface 130 from minimum distance D2min tomaximum distance D2max with respect to axis 110 and back in a repeatingcycle.

[0087] In a preferred embodiment of apparatus 100, when at minimumdistance D2min, each edge seal folder 132 is separated from adjacentedge seal folders 132 by a stationary anvil 310 that provides a cuttingsurface for a web cutting device, such as rotary knife 320. Stationaryanvil 310 is stationary with respect to rotating portion 300, and canbe, for example, a permanently affixed (to rotating portion 300),relatively rigid member having a relatively smooth cutting surface.

[0088] Rotary knife 320, mounted separately from rotating portion 300,can have a plurality of cutting blades 322 that operate in timedsequence with rotary portion 300 such that cutting blades 322 sever edgeseal web material 150 thereby forming discrete edge seal portions 152.Other cutting methods can be utilized, such as laser cutting, high-speedfluid cutting, saw blade cutting, and the like. In the embodiment shownin FIGS. 4 and 5, rotary knife 320 is rotatable upon its axis ofrotation 324, which is parallel to axis 110 of apparatus 100. The rotaryknife 320 rotates in a timed relationship with rotary portion 300, suchthat the blade cuts continuous web 150 at a location corresponding to anarea between adjacent edge seals folders 132, while the respectiveadjacent edge seal folders are each at the position designated as 132A.

[0089] In another embodiment, web 150 can be perforated across its widthin a regularly repeating pattern of spaced apart, longitudinallyextending perforations (e.g., as is common in rolled toilet tissue). Inthis configuration, the distance between lines of perforation wouldcorrespond to the long dimension of edge seal folder 132. As each edgeseal folder 132 begins translating from the first position D2min to thesecond position, D2max, the lines of perforation can tear, therebyrendering each edge seal portion 152 discrete and operatively disposedon its respective edge seal folder 132.

[0090] In operation, therefore, as rotating portion 300 rotates edgeseal web material 150 is drawn onto second web surface 130 while secondweb surface is at minimum distance D2min. In FIG. 5, edge seal folders132 designated 132A are shown in the position in which edge seal webmaterial 150 is drawn or received onto apparatus 100 as rotating portion300 rotates about axis 110. To stabilize edge seal web material 150 inposition on second web surface 130, each edge seal folder 132 can havevacuum ports to which a partial pressure is applied. In this manner,edge seal web material 150 is held in position on each edge seal folderby vacuum, or suction, forces. The back tension applied to edge seal webmaterial 150 as it is drawn from its supply package (e.g., roll orfestoon), is controlled in conjunction with the forces supplied by thevacuum on edge seal folders 132 to ensure edge seal web material 150 isdrawn onto apparatus 100 in a stable, continuous process. Vacuum can beapplied in ways known in the art, such as by suitable arrangements ofpumps, tubes, and vacuum ports. Other means known in the art forstabilizing web materials can be used as well. For example, each edgeseal folder can have a light-tack adhesive applied to the surface 130such that edge seal web material 150 is removably adhered in place whencut into edge seal portions 152.

[0091] After having been cut by rotary knife 320, discrete edge sealportion 152 is disposed on its respective edge seal folder 132 in agenerally flattened (i.e., unfolded) position. Following the sequence ofmotion counter-clockwise (with respect to FIG. 5), the edge seal folder132 is translated via the interaction of cam followers 131 and cam track220 outwardly with respect to axis 110 and inwardly with respect toplane of symmetry 112 toward first web surface 120. At its maximumdistance from axis 110, which is D2max, second web surface 130 is at adistance from axis 10 that is essentially equal to that of first websurface 120. At this position, edge seal web portion 152 is adjacent toand partially overlaps continuous web 140.

[0092] Edge seal portion 152 is folded upon a longitudinal edge ofcontinuous web 140 to form edge seal 60 by a folding action of edge sealfolders 132. Edge seal folders 132 can be formed of two independenthalves, for example, such that one half can fold over onto the otherhalf, thereby making the C-fold of the edge seal portion 152, which canbe joined in a folded condition onto continuous web 140 as edge seal 60of the finished diaper. The folding action can be achieved by methodsknown in the art, for example by way of flexible hinged elementsoperated by mechanical linkage. The folding can be accomplished via beltdriven linkages, hydraulic linkages, servo motors, and the like,actuated in timed sequence with the rotary cycle of apparatus 100.

[0093] In a preferred embodiment, the folding action is achieved bylinkage controlled by the cam followers 131 of each edge seal folder 132when in a predetermined position relative to the rotating cycle ofapparatus 100. This arrangement provides positive timing control to thefolding step. In a preferred embodiment, a pair of cam followers 131 isassociated with each edge seal folder 132, with the two cam followersindependently moveable. In a preferred embodiment each such cam follower131 is biased against either the inner cam track surface 222 or theouter cam track surface 224. Biasing can be accomplished by means knownin the art, such as by spring loading, for example.

[0094] In another embodiment, each cam follower 131 can follow anindependent cam track that has a width only slightly greater than thediameter of its respective cam follower. In this embodiment there wouldbe no need for the cam followers to be biased, such as by springloading, each cam follower 131 would simply be guided by its ownrespective cam track to follow a path corresponding to the opposingsurfaces of the cam track 220. Such a design is depicted in FIG. 8,where each cam follower is disposed in its own respective cam track.However, in general, regardless of the actual arrangement of cams andfollowers, the preferred principle of operation is as describedhereinbelow.

[0095] As shown in FIG. 5, the inner cam track surface 222 and the outercam track surface 224 follow non-parallel paths in the region designatedas a region of increased cam track width 226. In region 226 the distancebetween the biased cam followers 131 increases to a maximum separation,and, following the cam track 220 in a counterclockwise manner, decreasesback to a minimum spacing, all in a smooth, uninterrupted manner. Theregion of increased cam track width 226 facilitates the temporaryspreading apart of cam followers 131, which spreading is linked byoperative linkage to the folding mechanism of each edge seal folder 132,as detailed below.

[0096] Thus, in the rotary cycle of apparatus 100, as rotary portion 300rotates, each edge seal folder 132 is urged in turn by way of the camfollowers 131 to region 226 at which time the edge seal folders 132 areactuated into a folding position for as long as the cam followers remainsufficiently separated. As cam followers 131 are urged closer togetherby the converging paths of the inner and outer cam track surfaces, theedge seal folders once again return to an unfolded configuration. Atthis stage in the cycle the edge seal portion 152 has been affixed asedge seal 60 to a longitudinal edge of continuous web 140, and the edgeseal folder 132 is now ready to be moved back into a position to againreceive edge seal web 150, and the cycle continues in a repeatingmanner.

[0097] In a preferred embodiment, the edge seal folder 132 is configuredfor relatively high-speed operation. That is, the mechanism of foldingpreferably permits the fold/unfold cycle to complete in a matter ofmilli-seconds.

[0098] One configuration found successful in high-speed operation isshown in FIGS. 7 and 8. Each edge seal folder 132 can comprise at leasttwo folding portions, a first folding portion 134 and a second foldingportion 136. The edge seal folders 132 can have more than one foldingportion, but at least two are necessary to form a C-folded edge seal 60.In operation, second folding portion 136 is rotated about axis 141 tofacilitate C-folding of edge seal portion 152 to form edge seal 60.

[0099] Because edge seal folder 132 preferably has a curved surfacewhich forms second web surface 130, second folding portion 136 ispreferably capable of inverting its curvature upon actuation of thefolding operation. That is, before folding, the second web surface 130of second folding portion 136 preferably forms what can be described asa convex surface. However, after the folding operation the second websurface 130 of second folding portion 136 forms what can be described asa concave surface, which together with the still convex second websurface 130 of first folding portion 134, can apply generally uniformfolding pressure along the length of folded edge seal portion 152.Therefore, second folding portion 136 is preferably pliable, bendable,or otherwise deformable to enable repeated bending cycles, such aspolyurethane, for example.

[0100] When each leg cuff folder 132 is in the web-receiving position,such as 132A in FIG. 4, the first and second folding portions 134, and136, are “opened” as shown in FIGS. 7 and 8, such that together theydefine a relatively flat second web surface 130. However, a slightoffset of the second web surface 130 of the first and second foldingportions 134, and 136 can be beneficial. By “offset” is meant a slightdifference in D2min between first and second folding portions 134, and136 with second folding portion 136 having a slightly greater D2min,such that upon rotation of second folding portion, as described below, agap is formed between first and second folding portions 134, and 136 inthe folded position. This gap can be predetermined and adjusteddepending upon the basis weight and/or thickness of the particular webmaterials 140, 150 utilized. In one embodiment, when in the open,unfolded position, there can be essentially no gap between first andsecond folding portions 134, and 136, along their adjacent edges.

[0101] In the embodiment shown in FIGS. 7 and 8, the first and secondfolding portions 134, and 136 are separately supported in aside-by-side, adjacent relationship, that is, they are not hinged orotherwise joined to one another. The first and second folding portions134, and 136 are disposed in an articulating relationship relative toeach other, such that one portion can be rotated or “flipped” 180degrees about axis 141 to achieve the folding of edge seal portion 152(not shown in FIGS. 7 and 8).

[0102] One suitable method of accomplishing high-speed folding of edgeseal portion 152 is shown in the schematic representation of FIG. 8.First folding portion 134 is mounted in a non-rotating relationship withrespect to edge seal folder 132. Second folding portion 136 isunattached to first folding portion 134 and is supported in a rotatableposition by mechanisms operatively linked to cam followers 131. In theembodiment shown, primary linkage 139 is operative attached by suitablepivot arms to one of the cam followers 131, specifically the inner camfollower relative to axis 110. With reference to FIG. 5, it can be seenthat the inner cam follower, following the inner cam track surface 222in the region of increased cam track width 226 moves inwardly withrespect to axis 110, thereby initiating the folding motion of edge sealfolder 132.

[0103] As inner cam follower moves, linkage 139 rotates belt drive 135to rotate in the direction indicated. Belt drive 135 moves drive belt137 which thereby turns at least one drive roller 131, which turns anassociated linkage connector 133, which itself is operatively connectedto linkage 138 which comprises a cooperating pair of links that areconfigured to facilitate a 180 degree fold over motion of second foldingportion 136. Other supporting links, shafts, bearings, and the like,which are not necessarily shown, can be configured in known ways tocomplete the linkage. Thus, there is direct mechanical linkage betweenthe cam track 220 and the first and second folding portions 134, 136that permits high-speed, synchronized, folding of edge seal portion 152to form edge seal 60 of a diaper being processed on apparatus 100. Thevarious components are shown in the folded configuration by the phantomlines of FIG. 8.

[0104] In a preferred embodiment, belt drive 135 has a diameter exactlytwice the diameter of drive roller(s) 131, such that as belt drive 135rotates through an arc of 90 degrees, drive roller(s) 131 rotate through180 degrees.

[0105] Once folded about a longitudinal edge of continuous web 140, edgeseal portions 152 are joined to continuous web 140 by methods known inthe art for assembling components of absorbent articles, particularlydisposable absorbent articles. In a preferred embodiment, edge sealportions 152 are affixed by adhesive, such as hot melt adhesive. Theadhesive can be applied to the continuous web 140 at locations intendedto receive the edge seal portions 152, or adhesive can be applied to onesurface of the edge seal web 150 prior to being cut by rotary knife 320.Adhesive can be applied by methods known in the art, includingextrusion, spraying, slot coating, or wiping. In one embodiment,adhesive is applied by extruding hot melt adhesive beads from adhesiveapplicators 350 placed to facilitate adhesive application to edge sealweb 150. The particular method and location of applying adhesive dependson the type of adhesive used, and its cure rate, and is not consideredcritical to the present invention. In one embodiment Findley H2031adhesive, applied by spraying onto edge seal web 150 was used.

[0106] In one embodiment, the edge seal web 150 comprises elasticmaterial, or highly elastic material, and is received onto edge sealfolders 132 as a tensioned web of material in an extended state. Onceapplied to the longitudinal edge of continuous web 140, the edge seal 60so formed can remain in an extended, stretched configuration. Oncecontinuous web 140 is cut and formed into a diaper, edge seal 60 canrelax, contract, and form a soft, gathered, finished cuff about the legportion of diaper 20. In one embodiment, edge seal web 150 comprisesnonwoven material comprising elastomeric strands of an elastomericpolymer, such as Kraton®, Lycra®, or Spandex® strands.

[0107] In one embodiment, edge seal web 150 comprises at least onestrand of elastomeric polymer strand(s) enveloped in a fold along onelongitudinal edge thereof. The width of edge seal web 150, including theedge having enclosed therein an elastomeric strand is adequate toprovide not only an edge seal, but also the integrated barrier cuff 61as shown in FIG. 3. Thus, upon folding, edge seal portion 152, having anextended width, forms not only edge seal 60, but integrated barrier cuff61.

[0108] In a preferred embodiment, edge seals 60 are not straight whenapplied to the longitudinal edge 50 of diaper 20 (and, therefore, notstraight when applied as edge seal portion 152 to a longitudinal edge ofcontinuous web 140). In a preferred embodiment, edge seals 60 follow thecontour of the concave-shaped portions of a diaper (in a flat-outcondition, as shown in FIG. 1) of a diaper having an “hourglass” shape.Therefore, in a preferred embodiment, because edge seal web 150 isreceived as a “straight” web, and edge seal segment 152 is thereforereceived in an “un-curved” configuration, each of first and secondfolding portions 134, 136 of edge seal folders 132 are segmented suchthat the segments can articulate with respect to one another. Sucharticulating segments are shown schematically in FIG. 9. As shown, firstand second folding portions 134, 136 each comprise segments, denoted inFIG. 9 as segments A, B, and C. However, in practice, the number ofsegments can be varied as necessary to achieve the curvature of edgeseal 60 desired. The segments can be separated by partial slits 142, andV-shaped openings 144. In this embodiment, guides 330 do not follow acompletely linear path, but as edge seal folder 132 nears D2max, guides330 deviate from linear, for example by twisting with respect to eachother. The exact path of guides 330 is difficult to describe in words,but results in at least one or both of segments 134A and 134Carticulating with respect to 134B, for example, such that slit 142 opensup in a V shape, and V-shaped opening 144 closes up, so that theinterface between first and second folding portions 134, 136 forms acurve, designated 146 in FIG. 9. Therefore, once folded upon thelongitudinal edge of continuous web 140, the resulting edge seal 60 canbe curved, following the contour of longitudinal edge 50 of the finishedarticle, as shown in FIG. 1.

[0109] While particular embodiments of the present invention have beenillustrated and described, it would be apparent to those skilled in theart that various other combinations and modifications can be madewithout departing from the scope of the invention. It is thereforeintended to cover in the appended claims all such combinations andmodifications that are within the scope of this invention.

What is claimed is:
 1. A disposable diaper comprising a topsheet, abacksheet, and an absorbent core disposed between said topsheet and saidbacksheet, said topsheet and said backsheet defining a periphery andlongitudinal edges, portions of said longitudinal edges defining legopenings when said disposable diaper is worn, said disposable diapercomprising on each longitudinal edge a discrete edge seal folded aboutand joined to said longitudinal edges at least at said portions of saidlongitudinal edges defining leg openings when said disposable diaper isworn, wherein said discrete edge seals do not extend the entire lengthof said longitudinal edge of said disposable diaper.
 2. The disposablediaper of claim 1 wherein said discrete edge seals are joined about eachof said longitudinal edges only at said portions of said longitudinaledges defining leg openings.
 3. The disposable diaper of claim 1 whereinsaid edge discrete seal comprises an elastomeric material.
 4. Thedisposable diaper of claim 1 wherein said discrete edge seal comprises anonwoven material.
 5. The disposable diaper of claim 1, wherein saiddiscrete edge seal comprises at least one elastomeric strand.
 6. Thedisposable diaper of claim 1, wherein said discrete edge seal furthercomprises a barrier cuff.
 7. The disposable diaper of claim I whereinsaid diaper exhibits an hourglass shape having inwardly-curved portionsof said longitudinal edges when in a flat-out state.
 8. The disposablediaper of claim 7, wherein said discrete edge seal is affixed only atsaid inwardly-curved portions of said longitudinal edges.
 9. Anapparatus for affixing a discrete edge seal onto a portion of alongitudinal edge of a continuous web, said apparatus having an axis ofrotation, and comprising: a) a first web surface disposed at a firstradial distance from said axis; b) an edge seal folder comprising asecond web surface disposed at a second radial distance from said axis,said second radial distance being variable between a first minimumdistance and a second maximum distance, wherein at said second maximumdistance said second radial distance is substantially equal to saidfirst radial distance; c) said edge seal folder adapted to receive edgeseal material on said second web surface at said first minimum distanceand to fold and affix said edge seal material as a discrete edge sealonto a portion of said longitudinal edge of said continuous web at saidsecond maximum distance.
 10. The apparatus of claim 9, wherein saidfirst radial distance is fixed and constant.
 12. The apparatus of claim9, wherein said edge seal folder comprises at least two separateportions capable of articulating with respect to one another to foldsaid edge seal onto said portion of said longitudinal edge of saidcontinuous web.
 13. The apparatus of claim 9, further comprising asadhesive applicator for applying adhesive to portions of said edge sealmaterial or said portion of said longitudinal edge of said continuousweb.
 14. The apparatus of claim 9, further comprising a cutting devicefor cutting said edge seal material into discrete edge seal portions.15. A method of affixing a discrete edge seal onto a predeterminedportion of a longitudinal edge of a continuous web, the methodcomprising the steps of: a) providing said continuous web; b) providinga continuous web of edge seal material; c) providing an edge seal folderthat is translatable radially outward with respect to an axis ofrotation between a first minimum distance and a second maximum distance;d) receiving a portion of said continuous web of edge seal material upona surface of said edge seal folder; c) applying adhesive to either ofsaid portion of said continuous web of edge seal material or saidcontinuous web in a predetermined location; f) cutting off said portionof said continuous web of edge seal material from said continuous web ofedge seal material; g) retaining said portion from said continuous webof edge seal material upon said surface of said edge seal folder; h)translating said edge seal folder from said first minimum distance tosaid second maximum distance; i) folding said portion of said continuousweb of edge seal material about said predetermined portion of saidlongitudinal edge of said continuous web; and j) joining said portion ofsaid continuous web of edge seal material to said predetermined portionof said longitudinal edge of said continuous web.